Recording and reproducing attachment for phonographs



w.' H. GILMAN.

RECORDING AND REPRODUCING ATTACHMENT FOR PHONOGRAFHS.

APPLICATION FILED MAR. 8, 1920.

Patented Aug. 30, 1921.

3 SHEETSSHEET I- w; i d a z W. H. GILMAN.

RECORDING AND REPRODUCING ATTACHMENT FOR PHONOGRAPHS.

APPLICATION FILED MAR. 8, 1920.

1 389,429. t nt d Aug. 30, 1921.

3 SHEEIS-SHEEI 2.

KO T

cm 6 Q INVENTOR TORNEY W. H. GILMAN.

RECORDING AND REPRODUCING ATTACHMENT FOR PHONOGRAPHS.

APPLICATION FILED NAILS. 1920.

1 3 9 429 Patehted Aug. 30, 1921.

XNVENTOR WILLARD H. GILMAN, OF NEW YORK, N. Y., ASSIGNOR, BY

FEICE.

mun assremmnrs',

PATENT-0 TO JOHN ALMOVICKAR, OF NEW YORK, N. Y.

A RECORDING AND REPRODUGING ATTACHMENT FOR PHO'N'OGRAPHS.

Application filed March 8, 1920. Serial No. 364,317.

To all whom it may concern:

Be it known that I, WILLARD H. GILMAN, a citizen of the United States, and resident of New York, in the county of New York and State of New York, have invented certain new and useful Recording and Reproducing Attachments for Phonographs, of which the following is a specification.

This invention relates to phonographs and particularly to an attachment for disk type phonographs which includes a mechanism "whereby the records may be recorded and .reproducer heads and which at reproduced on any standard disk type phonograph. The objects of this invention are to provide a mechanism of this kind which isv readily detachable and replaceable; which takes care of irregular movements of the turn table and the turn table stem; which provides for adjustments for different sizes of machines; which may be raised and turned back from the turn table while the latter isin motion and may be replaced while it is in motion; which permits the horn to be turned in any direction without disturbing the mechanism or the position of the phonograph; which automatically raises the stylus from the record when the machine has moved to a predetermined position and which includes means for raising and lowering the stylus and diaphragm head as ma be desired. Other objects will appear li'om the following specification and drawings, in which Figure 1 is a plan view with the mechanism case in section. Fig. 2 is a vertical elevation in section through the center line of the mechanism. Fig. 3 is a detail ofthe support on line a a, Fig. 2. Fig. 4 is a detail of the voice tube and Fig. 5 shows a vertical elevation of the device complete.

This invention also consists of an attachmentcarrying .a voice tube from a center stem which terminates in the recording or the opposite end leads to a horn connection which swivels on the top of the mechanism and may be turned in any direction. The center stem of the voice tube is rotated bywa mechanism driven from the stem of the turn table through a universal joint and suitableworm geari thus causing the recording or reproducing head to describe an arc across the face of the record. This drive operates of these moving parts.

through a friction clutch which enables the stylus to be readily positioned anywhere on the face of the record. The invention also includes means whereby its vertical height may be adjusted to suit different heights of turn tab-1e and the entire mechanismmay be turned back upon its support to enable records on the turn table to be changed.

In the drawings, 11 represents the cab-inet of a phonograph of the usual type, having a mechanism driving the stem 12 which carries the turn table 13 and upon which the record 14 rests. This mechanism is made of 'suflicient length to take in the largest size of turn table in commercial use as indicated by the dotted extension 13. Near the edge of the turn table the curved base plate 15 is located and secured to the cabinet 11 by suitable screws 18 in the slotted holes 16.. These holes are slotted with the object of enabling thedriving mechanism to be accurately positioned over the stem 12 of the turn table.

To the base plate 15, the vertical support 21 is secured by knurled nut 23 and the dowel pins 22. This nut is held to this stand by the slotted plate 24. As shown in Fig. 3 this vertical support is semi-circular in section and carries an inner semi-circular member 27, having a positioning rib 28 engaging a corresponding groove in 21. A vertical slot 25 is provided in 21 through which the screw 26 passes and is used to clamp the parts 21 and 27 securely together thus permitting vertical adjustment of the member 27 which terminates in the lugs 29 supporting the hinge pin 30 and the extension 31 of the main casting 32, thus supporting the entire mechanism at this end.

The main casting 32 is provided witha base plate 33 to inclose the operating mechanism thereby preventing dust and wax from the record from interfering with the working parts and also to act :as a bearing for certain The main casting terminates in a'hemisphere 34 over the stem of turn table and has the extension 35 at the opposite'end to house the gearing and voice tube as shown. y

The stem of theturn table is provided with a member 36. which grips the stem by a spring action and terminates in a cu -shaped extremity as indicated at 37. T is cup- Specification of Letters Patent. Patented Aug. 30, 192 1.

shaped extremity is formed to take the ball 40 and has a pin 38 which fits a slot in this ball. This ball connects by a stem 39 with a corresponding ball 42 in the end 41 of vertical shaft 45. A pin 43 fits the corresponding slot in this ball and the edges of 41 are spun over as indicated at 44 so that this connection is secured to the part 41. It will be observed that pins 43 and 38 are placed at right angles to each other the whole construction forming a universal joint with the object of compensating for eccentricity in the stem 12 of the turn table. This is a matter of considerable importance in view of the radius of the voice tube leading to the stylus and the desirability of obtaining as erfect a spiral as possible on the record. be noted further, that the casting 32 may be turned over on the hinge 30. 'Since the ball 40 is-not secured in cup 37 this operation may be performed without stopping the turn table; also, the mechanism may be replaced in the operating osition without stopping the turn table. in 38, by the rotation of the turn table, will readily find the groove in ball 40 when this rotation is performed.

The shaft 45 carries the worm 46 engaging worm wheel 47 mounted on shaft 48, pivoted at 49 in hemisphere 34 and at the opposite end pivoted in an eccentric bearing 50 locked in positio by screw 51 and carrying the worm 52 to mesh with worm wheel 53. The eccentric bearing 50 enables a close adjustment between the worm 52 and worm wheel 53 thereby preventing backlash in the mechanism. 8

The worm wheel 53 is pivoted on the center stem of the voice tube 54 and is free to turn thereon. This voice tube has a collar 56 secured thereto and between this collar and the worm wheel a leather washer is placed to provide sliding friction.- This friction is regulated by flat spring 57 bearmg on the collar 56 and held in tension by the collar 58 secured to the voice tube by pin 59. Collar 56 is secured to the voice tube 54 by wings 56 which engage slots 54 in the tube, this-collar therefore has a free vertical motion responding to spring 57 while rotatmg with stem 54. The verticalstem of the voice tube ends in an aperture at 60 in the casting 32. From this arrangement it will be observed that the center stem of the turn table drives the worm wheel 53 at a greatly reduced speed and this wheel in turn, by

means of the friction secured through the leather washer 55 and spring 57, carries the vertical stem of the voice tube with it as it rotates. However, the voice tube can easily be ositioned by hand.

be top of the mechanism contains the termlnal or elbow of the voice tube 61 to which the horn 101 is attached. This part curved as shown may be rotated on itsv sup port by means of flange .62'secured in 1.

t will tion by collar 63 and screws 64. A fiber washer 65 is provided between this part and the main casting 324:0 guard against the possibility of metallic sounds if this part should work loose.

It will be noted that this provides a clear, unobstructed voice passage from the horn to the tone arm 67 which leads to the diaphragm head. The position of the tone arm on the record is indicated by the index 69 and the index finger 68 shown in Fig. 1.

The tone arm has a spigot71 having a socket joint supporting a socket member 73 pivoted at 7 2' and normally held in an elevated position by spring 74 as indicated in section by Fig. 4. On this socket member the diaphragm head 75 is secured either by friction or by a set screw as indicated at 76 in the collar 76.

The diaphragm head 75 carries a suitable diaphragm 77 to which the lever 78 is secured andterminates in the stylus 79. In the construction shown of a reproducing head, the diaphragm is inverted and the lver positions the stylus a considerable distance in front of the head. It is found in practice that the diaphragm head resting upon the rotating record is subject to considerable centrifugal action from the turntable; this action is proportional to the speed of the turntable and to the weight of the head measured from its center of gravity. A diaphragm head constructed as shown in Fig. 5 with a ball and socket connection to the tone arm tends to move on this connection under the centrifugal action of the turntable. The

construction just described with the lever p0- sitioning the stylus in front of the diaphragm head places the'center of gravity of the dlaphragm head close to the socket joint while the stylus is properly positioned on the record, thus reducing the tendency of the head to jump the grooves under this centrifugal action.

When the tone arm moves in toward the center of the turn table, the diaphragm head is automatically raised from the record. This may also be effected manually by use of the toggle lever 83 82 and secured by spring 84. When in the position shown in Fig. 2, the spring tends to hold this lever downso that stop 88 engages V bracket 82 thereby releasing the diaphragm head to act on the record by gravity. On the other hand, when this lever is elevated, the spring tends to hold it elevated and it, in turn, ra'ises diaphragm head from the record. This is secured by means of the wire loop 80 pivoted at 72 and having an extension 81 terminating in 100 .86 under the extremity 85 oflever 83.. hen this lever is elevated loop 86 is depressed thereby raising loop 80 and the diaphragm head with it. When the tone arm moves toward the main casting-32.5117 extensien .99 2 thi seating pivoted at 87 to bracket carries a screw 91 to engage the inclined exattachment for tension 92 of lever 83 and automatically tilts this lever over the toggle, thus raising the tone arm head from the diaphragm when it has reached this position on the record. Screw 91 enables this tilting position to be varied.

Attention is called to the fact that the spring 74 in socket member 73 serves the double purpose of holding this member in a vertical position when the diaphragm head is removed, thereby making it easier ,to replace the diaphragm head and it also absorbs part of the j a-r caused by lowering the stylus on the record and thus guards against breaking the jewel of the stylus or injuring the record.

Th base plate 15 is provided with bosses 17 on either side drilled to support the horn crane-100 carrying the horn 101. This enables the horn crane to be positioned on either side of the mechanism while the swivel tube 61 enables the horn to be directed in any direction'relative to the mechanism itself.

This invention provides a very effective phonographs in which only one member is secured to the phonograph cabinet; where the mechanism itself may be quickly detached or replaced by the operation of one screw; where it may be turned over while the machine is used for other purposes and quickly brought into use again; a machine that is adapted to various sizes of turntables and. thickness of record and that will adapt itself to the irregularities of the operating mechanism without transmitting these irregularities to the record itself. The adjustment of the vertical support secured to the phonograph enables the height to be adjusted so that the weight of the entire mechanism is carried by this support and the arm 32 is supported above the turntable as a cantaliver. This relieves the weight of the arm from the universal joint and secures a smooth and even drive-when the stem is running out of true.

Having thus described my invention I claim:

1. In a phonograph attachment a turntable mounted for rotation, a mechanism secured to the case of said phonograph and extending over said turntable, said mechanism operably connected with the stem of said turntable .and driving a horizontal gear, a vertical voice tube centered in said gear and held in engagement therewith by spring friction, said voice tube having a horizontal arm terminating in a diaphragm head, substantially as descibed.

.2. In a phonograph attachment,'the combination of a turntable mounted for rotation, a mechanism having a base secured to the case of said phonograph and a horizontal gear operably connected with said turntable, a voice tube having a vertical section can gear and a horizontal arm connection with said vertical section terminating in a diaphragm head.

4. In a phonograph attachment, the combination of a turntable mounted upon a rotating stem, a socket member engaging said stem, a mechanism including a gear train pivotally mounted on a base secured to the case of said phonograph and having an arm extending above said stem arranged to turn vertically on said pivot, a vertical shaft in said arm connecting with said gear train, a ball connection extending from said shaft and fitting said socket member, means for rotatably engaging said member with said ball and means whereby said mechanism may be turned back on said pivot, or replaced, without disturbing the rotation of said turn table.

5. In a phonograph attachment, the combination of a turntable mounted upon a ro tating stem, a socket member engaging said stem, a mechanism including a gear train mounted on a base secured to the case of said phonograph and having an arm extending above said stem, a vertical shaft in said arm connecting with said geartrain, a double ball and socket connection between said vertical shaft and said socket member to compensate for eccentricity of said stem, said gear train arranged to drive a diaphragm head across said turntable.

6. In combination, in a phonograph including a revolving turntable, a mechanism supported by the case of said phonograph and extending above said turntable, a horizontal tone arm supported by said mechag nism and arranged to move across the face/ of said turntable, a lever pivoted to said 115 tone arm, a diaphragm head pivotally secured to said tone arm and means associated with said mechanism cooperating with said lever whereby said head is automatically elevated when said tone arm reaches a predetermined position.

7. In combination, in a phonograph including a revolving turntable, a mechanism supported by the case of said phonograph, a horizontal tone arm supported by said mechanism and arranged to move across the face of said turntable, a diaphragm head pivotally secured to said tone arm, a toggle lever mounted on said tone. arm and arranged when in one position to elevate said 180 diaphragm head and when in another position to lower said head.

8. In combination, in a phonograph including a revolving, turntable, supporting a record, a mechanism supported by the case of said phonograph, a horizontal tone arm supported by said mechanism and arranged to move across the face of said record, a diaphragm head pivotally secured to said tone arm, a toggle lever secured to said tone 10 arm for raising and lowering; said diaphragm head and adjustable means secured to said mechanism for operating said to gle. Signed at New York, in the county of ew York and State of New York this 6th day-of 15 March, A. D. 1920.

WILLARD H. GILMAN. 

